He had earlier been acquitted of the similar charges in 2005. The court ruled that his preparations were rudimentary and he posed no real threat despite possessing plans of Schiphol airport, a power station and the parliament building.

In an embarrassment for the Dutch authorities Azzouz was rearrested shortly after on suspicion of a new plot and later convicted under tougher new laws.

Today an Amsterdam court, which had been ordered to reassess the case after the prosecutors' appeal, found those first plans had posed a threat and sentenced Azzouz to four years, a spokesman said.

Prosecutors had sought a six year sentence.

Azzouz was initially arrested in a police crackdown following the murder of filmmaker Theo van Gogh in 2004 by another Dutch-Moroccan, Mohammed Bouyeri.